1. Field of the Invention
The present invention relates to a probe apparatus for inspecting objects of inspection, such as packaged logical circuit elements, for electrical properties.
2. Description of the Related Art
As shown in FIG. 15, a probe apparatus A generally comprises a test head D, which can be electrically continuous with a probing card C attached to an apparatus body B, a support E for supporting the head D for rotation, and a rotation drive mechanism F. The mechanism F causes the support E to rotate the head D in a direction such that terminals of the head D come into contact with or separate from terminals of the card C. After the test head D and the probing card C are thus made electrically continuous with each other, an object of inspection, such as a semiconductor wafer W, is inspected for electrical properties.
More specifically, a head plate (not shown) is mounted on the probe apparatus body B by means of, for example, hinges, thus forming a top face of the body B. The head plate can be swung open to the rear side of the apparatus body. An opening is formed substantially in the center of the head plate, and an insert ring (not shown) is attached to the opening. The probing card C is removably attached to the insert ring by means of a card holder. The card C is overlain by the test head D, which is electrically continuous with the card C. The test head D is mounted on one side face of the apparatus body B by means of, for example, a rotating shaft G. In replacing the probing card C or internally inspecting the apparatus body B, for example, the head D is rotated toward the one side face of the apparatus body, as indicated by two-dot chain line in FIG. 15. Thus, the head D is retreated to a position such that it is situated on the rear side of the apparatus body without interfering with the head plate.
The electrical continuity between the test head D and the probing card C is established by means of a performance board H or connecting ring I. The head D contains therein a power source for samples, which applies voltage to an IC chip on the semiconductor wafer, and pin electronics (not shown), which include an input unit for introducing outputs from the IC chip into a measuring unit. The pin electronics are connected electrically with a plurality of electronic component circuits mounted on the performance board H. Terminals of the electronic component circuits are arranged concentrically on the lower surface of the board H, and are pressed against spring probes (not shown) that are arranged concentrically on the upper surface of the connecting ring I, whereby the test head D is made to be electrically continuous with the probing card C.
Thus, in the probe apparatus A constructed in this manner, the test head D is rotated toward the probing card C so that the terminals of the head D are pressed individually against the spring probes of the card C, whereby the head D and the card C are connected electrically with each other.
As the terminals of the rotating test head D are pressed against their corresponding spring probes of the probing card C, however, all the terminals of the head D are not simultaneously pressed against the spring probes. Those terminals whose radii of rotation are relatively short are first pressed against their corresponding spring probes, and those terminals whose radii of rotation are longer are then pressed against their corresponding pins. In other words, the terminals of the test head D are pressed against their corresponding spring probes by priority of the shortness of the radius of rotation. In this process of operation, therefore, those spring probes which are brought into contact with the terminals with shorter radii of rotation are more liable to be damaged by a diagonal force or bending stress. In consequence, an operator must continually check the spring probes for the extent of damage and, if necessary, replace the spring probes.